Introduction to Building Performance Analysis

8/12/2019 Introduction to Building Performance Analysis

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Introduction to Building Performance Analysis

Environmental Impacts and Buildings

Mathematical models of global climate change have linked a human-driven increase in GHGs

to anincrease in global temperatures(especially in the past !" years# since the industrial

revolution$% &he primary source of this increase in GH's has been attributed to the emissions

generated by the use of fossil fuel-based energy%

Buildings account for 40%of orldide energy use ) hich is much more than

transportation% Moreover# energy use in the form of electricity often drives the largest

environmental impacts%

&hese e*act impacts can +uantified by lifecycle assessment (LC!# ,linkthe most thorough

ay to determine the environmental impacts of a design% .'As can measure greenhouse gas

(units " C#$e " C#$ euivalent!to measure global arming potential# or might measure

other things like human health# ater# and land-use impacts% /ou may hear the ord

0embodied energy1 or 0embodied carbon1 2 this refers to the energy or greenhouse gas

emissions caused throughout an ob3ect4s lifecycle% Alternatively# sometimes an overall

normali5ed score is used to combine many kinds of impacts into a single number (i%e% 6co-

Indicator 77$%

Lifecycle Assessment (LCA) is a foundational tool for sustainable design. It is a way of quantifying

the environmental impact of your designs so that you and your customers can make more

informed decisions. o learn more about LCA! see our brief primer below that introduces the basic

terms! methodologies! and tools."link#

A "8 .'A study found that 09pecifically ithin commercial buildings# the use and operation

phase of the material and building life cycle is so dominant that the impacts of construction#

demolition:disposal# and transportation are nearly irrelevant for most traditionally

constructed buildings%1
http://sustainabilityworkshop.autodesk.com/products/lifecycle-assessmenthttp://sustainabilityworkshop.autodesk.com/sites/default/files/core-section-files/lcaprimer_autodesk-sworkshop_final.pdfhttp://sustainabilityworkshop.autodesk.com/sites/default/files/core-section-files/lcaprimer_autodesk-sworkshop_final.pdfhttp://sustainabilityworkshop.autodesk.com/products/lifecycle-assessment


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&et 'ero Energy Buildings

;or high performance building design# it4s most useful to measure and compare designs using

absolute energy and resource metrics% &hese comparisons are ob3ective# universally

applicable# and apples-to-apples%

educir cargas energticas

% iseCo de estrategias pasivas

@% ptimi5aciFn de sistemas activas

D% >ecuperaciFn de energa

!% GeneraciFn energtica in-situ

J% 'omprar e*cedentes energticos


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)esign *oals for +igh ,erformance Buildings

High performance buildings aren4t only about energy% &hey also need to perform ell for

occupants%

#ccupant Comfort

hermal Comfort

'reating comfortable conditions is one of the biggest uses of energy in buildings and it is also

critical to the happiness and productivityof its users% &o keep people comfortable you need

to provide the right mi*ture of temperature. humidity. radiant temperature and air

speed% &he right level of these variables depends on hat activity is occurring# ho active the

people are# and hat they are earing% 6veryone has slightly different criteria for comfort# so

comfort is often measured by the percentage of occupants /ho report theyre satisfied

ith the conditions%

1isual Comfort

Maintaining visual comfort means ensuring that people have enough light for their activities#

the light has the right +uality and balance# and people have good vies% .ighting is often

measured either by the amount of light falling on a surface (illuminance!or the amount

of light reflecting off of a surface (luminance! % &hese are ob3ective measures# but ho

people e*perience this light is often sub3ective% Good visual comfort also generally means that

as much of this light is natural light as possible% Good controls can automatically balance

natural and artificial lighting%.earn more about natural and artificial lighting and ho to measure it% ,link

ir 2uality

;resh air re+uires a certain percentage of outside air circulating into spaces% 'lean air

re+uires pollutant and pathogen levels to be belo certain thresholds% Air can be kept fresh

ith high ventilation rates. either using natural ventilation such as operable /indo/s.

or active systems such as +1C fans and ducts% 'lean air can be achieved by filtering air#

by flushing spaces ith fresh outside air# and by not contaminating the air ith impurities

from the building# such as volatile organic compounds from paints or materials% ,link

coustic Comfort

Ho humans perceive sounds and loudness is a sub3ective measure% Hoever# you can create

a comfortable environment by controlling ob3ective measures like decibel level(sound

pressure$# reverberation time# and the sound reflection and dampingproperties of

materials% 'reating barriers and sound breaks beteen sources of noise is important% /ou can

optimi5e room shape and si5e to reduce echoes and reverberation% And you can use acoustic

tiles on ceilings and alls to dampen the sound%
http://sustainabilityworkshop.autodesk.com/buildings/lighting-and-daylighting-designhttp://sustainabilityworkshop.autodesk.com/buildings/indoor-air-qualityhttp://sustainabilityworkshop.autodesk.com/buildings/lighting-and-daylighting-designhttp://sustainabilityworkshop.autodesk.com/buildings/indoor-air-quality


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3esource se 5 Buildings

6aterial se

Materials have their on environmental impacts from e*traction and production# and they

also hugely affect the thermal# visual# and acoustic performance of the building% Materials arealso important because they create the physical space that your building occupants

e*perience%

Embodied energy or embodied carbon can be used as a measure of the environmental

impactof a material4s e*traction# processing# manufacture# and distribution%

Energy ystems

6nergy systems produce# use# convert# and store energy for the building% In high performance

buildings these systems need to be both efficient and effective%

6nergy use in buildings is also one of the biggest costs throughout the lifetime of a building%

&his can be measured by looking at the 7ilo/att hours per year. per unit area(6nergy Ese

Intensity or 6EI$% Being energy efficient means getting the most out of the systems and

technologies that you4ve chosen to use% &his can be measured by the coefficient of

performance of the e+uipment%

Generally# the architect4s ork defines the energy 0demand1 (their design places re+uirements

and constraints on ho the building orks$ and engineers define ho to 0supply1 this energy%

8ater se

Kater is measured in terms of both +uantity and +uality% &he florate of fi*tures like faucets

and the storage capacity of tanks and cisterns are different ays to measure +uantity% Kater

+uality can be measured in a variety of ays# and you need different +ualities for different

uses% Khether the ater is potable or not dictates ho it can be used% Indicators like pH#

dissolved organics# suspended solids# and turbidity help measure +uality% Also# plumbing

systems that separate potable ater# greyater# and blackater can help get the most out of

every drop%


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Building )esign ,rocess

*reen Building )esign ,hases

&he process outlined ne*t more closely resembles integrated pro9ect delivery (I,)!# ,link

ith tighter collaboration# and shared goals# beteen stakeholders and design disciplines%

Many pro3ects# hoever# are still done using the esign-Bid-Build process%

8% Predesign

% 'onceptual esign

@% esign evelopment

D% etailed esign L ocumentation

!% 'onstruction

J% perations and Maintenance

,redesign

9tudying the e*isting conditions of the building site% It4s also important to set targets for

sustainability# like achieving net 5ero energy or certifying the building through a program like

.66% /ou4ll develop and revisit these +uantitative and +ualitative goals as you move through

all of the phases%

Conceptual )esign

/our first designs ill e*plore alternate building and system design options% &he primary focusfor energy efficiency during this phase are daylighting and glare# natural ventilation# shading

and solar gains# distribution of internal loads# and envelope materials%

)esign )evelopment

uring this phase you4ll begin problem solving and studying the details of alternate design

concepts chosen in the conceptual design stage%

)etailed )esign and )ocumentation

nce the final design is aligned upon# the team ill prepare for construction by creating a fully

articulated design and building information model% A final version of the simulation and

energy analysis ill document the target energy performance and provide a benchmark for

validation during the construction phases% Kith this information you4ll also be ready to finali5e

many of the documents you4ll need for building certification systems like .66%

Construction

Kith the design fully orked-out by the engineers and architects# you4ll no ensure that the

construction team can efficiently build the pro3ect to the design and performance

specifications%

&his is hen building materials are usually purchased% ften the specifications allo like-or-
http://bimcurriculum.autodesk.com/case-study/integrated-project-deliveryhttp://bimcurriculum.autodesk.com/case-study/integrated-project-deliveryhttp://bimcurriculum.autodesk.com/case-study/integrated-project-delivery


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better4 substitutions% A detailed BIM model and coordinated energy model ill help assure

that any substitutions ill actually meet performance re+uirements%

#perations and 6aintenance

nce all of the occupants move in# you4ll ant to continue monitoring energy use and thermal

comfort to confirm that the building is running smoothly# to continually improve operations(continuous commissioning$# and to detect errors and faults in e+uipment or controls early%

ngoing monitoring and maintenance is important to ensure the building continues to

perform ell%

Also# because changes are usually made during construction# you ill revise the BIM model

and the details of the energy model according to the final design%

Building ,erformance nalysis (B,!

In addition to driving a more efficient overall design process# BIM is poerful for sustainable

design because it can help you iteratively test# analy5e# and improve your design% &his is called

Building ,erformance nalysis (B,!%

9tatistician George 6%P% Bo* is +uoted as saying? :ll models are /rong. but some are

useful;


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)esign ,hases 5 BI6 Level of )etail

uring the design process# you4ll be making both big and small decisions% ften the decisions

you4ll make move from a larger scale (overall building form! to smaller scale

(components and materials for a shading device!%

,redesign phase

At this point of design# try not to be frustrated about not taking to many decissions% &his is all

about creating the references around the pro3ect# and making sure that climate and physical

conte*t are implemented in your design development%

Enderstanding the climate ill give the team a good idea of hat kind of passive design

strategies ill be appropriate for the pro3ect% 6arly sun studies can yield additional insights

that ill inform conceptual design strategies%

&ools to consider

'ivil @ or >evit (site map$

Oasari or >evit (surroundings# e*isting conditions$

6cotect Keather &ool

Conceptual )esign phase

uring conceptual design# the model usually consists of overall building massing(height#

volume# location# orientation$# along ith basic assumptions about construction type and

building schedules% Most details of the building ill not be knon at this time# so conceptual

energy models ill be built ith simple volumes and areas. default values. and genericmaterialsand e+uipment% 'onceptual models help the team align on high-level decisions like

the form# orientation# and program of the building%

&ools to consider?

Oasari

>evit

6cotect

)esign )evelopment

&hese models consist of generali5ed systems or assemblies ith appro=imate+uantities#

si5e# and shape% &he geometry is built from generic elements but more refined assumptions

are made on constructions# materials# e+uipment%

)etailed )esign and )ocumentation

Construction

#perations and 6aintenance


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oft/are /or7flo/s

Getting the most out of softare analysis re+uires that you think critically about hen and

ho to use it% Ask yourself? Khat are you trying to decide and optimi5e Khat4s the right tool

for the 3ob

Here4s a conceptual frame/or7that e use throughout this course for :2uic7 3eferenceno/ing *oals and 6etrics

&he first step of the analysis process is creating a clear picture of /hat youre trying to

learnand hat aspects of the design you4re trying optimi5e% &hat can help you understand

hat tools to use# and hat to look for in the analysis results%

sing ools for imulation 5 nalysis

nce you kno your goals and metrics# you can start running simulationsand doing

analysis% It4s best to first do some back-of-the napkin calculations to have an idea of /hat

the results should bebefore you run the simulations%

)esign #ptimi?ation )ecisions

&he results of your simulation are only useful if you analy5e them and can use them to

improve the design% &his means comparing your results ith other design options# industry

baselines and best practices# and your e*pected results%

It4s important to pay attention to patterns and anomalies in the results# identify sensitivity ofdesign parameters# and understand the role of various parts of the systems% /our

analysis should focus on understanding and improving the variablesthat are driving the

performance and cost of your design%

By folloing this process# you4ll be prepared to make an informed design decision%

&he original inspiration from this ork came from an Autodesk Eniversity Presentation by

Asb3orn .evring and aniel


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utodes7 Building )esign ools

Autodesk makes a host of products for building design% Autodesk4s core BIM tools ith BPA

capabilities are? >evit# Oasari# and Green Building 9tudio%

*reen Building tudiois a eb-based simulation engine for hole building energy

analysis% It is based on the 6- simulation engine and poers the hole-buildingenergy analysis tools across Autodesk products% It can perform analysis on any gbQM.

file and does not have modeling capabilities%

3evitis Autodesk4s flagship BIM product% It is a full-featured parametric building

information modeling platform for use throughout the design process% >evit models

use 0Building 6lements1 like alls# roofs# indos# and floors to create @ models%

&here are also conceptual massing capabilities# using basic shapes to model building

form and orientation earlier in the design process% In addition to architectural design# it

has tools for M6P design and structural design%

1asariis a simplified# parametric BIM tool that uses the same modeling conventions as>evit4s conceptual massing tools 2 and the same file format as >evit%

8hole Building Energy nalysis

Green Building 9tudio is Autodesk4s core hole building energy simulation engine# and poers

the analysis in both >evit and Oasari%

3evitsupports energy analysis for both conceptual formsand detailed

architecturalmodels%

1asarisupports energy analysis only for conceptual forms%

,erformance-based )esign tudies

It includes studies like sun path. solar radiation. /ind. airflo/. climate. and daylighting%

utodes7 3evitand 1asarihave some additional built-in capabilities for doing

performance-based design studies%

utodes7 Ecotectis a more speciali5ed tool that e*cels at these types of studies%

$hole building energy simulation results from %reen &uilding

'tudio

$ind flow and solar radiation studies based in

Autodesk asari.

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Introduction to Building Performance Analysis